This document discusses boilers, including their purpose, classification, components, and maintenance. It begins by explaining that a boiler is a closed vessel that transfers heat from fuel combustion to water to produce steam. It then classifies boilers based on factors like orientation, tube configuration, firing method, pressure, portability, and number of tubes. The document also describes key boiler components like feed pumps, injectors, economizers, and air preheaters. It concludes by discussing maintenance aspects such as performance assessment, blowdown, and feedwater treatment.

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2. SADIA WAZIR
ROLL # 25
BOILER
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3. INTRODUCTION
Boiler is a closed vessel in which the heat produced by
the combustion of fuel is transferred to water for its
conversion into steam at the desired temperature and
pressure.
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4. BOILER
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5. Why we use boiler ?
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 A boiler is a device used for generating:
a) Steam for power generation
b) Hot water for heating purpose

6. PRIMARY REQUIREMENT OF BOILER
 The primary requirements of steam generators or
boilers are:
a) The water must be contained safely
b) The steam must be delivered safely in desired
conditions as regards its pressure, temperature, quality
and required rate
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7. FACTORS AFFECTING THE CHOICE OF
BOILER
The selection of type and size of a steam boiler depends upon
the following factors:
 The power required and the working pressure
 Geographical position of the plant
 Availability of fuel
 Supply and quality of feed water
 The probable load factor
 Space available
 Labor available
 Steam pressure and superheat desired
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8. CLASSIFICATION
The Boilers may be classified as under:
 Horizontal boiler, vertical or inclined boilers
 Fire tube and water tube boilers
 Externally fired and internally fired boilers
 Forced circulation and natural circulation boilers
 High, medium and low pressure boilers
 Stationary boiler and portable boiler
 Single tube boilers and multi tube boilers
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9. BOILER ACCESSORIES
Feed pump
Injector
Economizer
Air pre-heater
Superheated
Steam separator
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10. FEED PUMP
Its a pump which is used to
deliver feed water to the boiler.
 The appliances in common use
for delivering the feed-water
into the steam boilers are:
a) Reciprocating pump
b) Rotary pump
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11. INJECTOR
The function of an injector is to feed water into the
boiler. It is also used where the space is not available for
the installation of a feed pump.
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12. ECONOMISER
 An economizer is a device in which the waste heat of the
flue gases is utilized for heating the feed water.
 Economizer are of two types :
 Independent type, and
 Integral type
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13. AIR PREHEATER
The function of the air pre-heater is to increase the
temperature of air before it enters the furnace.
It is generally placed after the economizer.
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14. CLASSIFICATION
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15. HORIZONTAL, VERTICAL OR INCLINED BOILER
 If the axis of the boiler is horizontal, the boiler is called
horizontal if the axis is vertical, it is called vertical boiler
and if the axis is inclined it is called as inclined boiler.
 The parts of horizontal boiler is can be inspected and
repaired easily but it occupies more space. The vertical
boiler occupies less floor area.
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16. FIRE TUBE BOILER
In the fire boilers, the hot
gases flows inside the tubes
and the water surrounds the
tubes
 Relatively small steam
capacities (12,000 kg/hour)
 Low to medium steam
pressures (18 kg/cm2)
 Operates with oil, gas or
solid fuels
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17. ADVANTAGES
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 Fire tube boiler is so easy to use, operate, clean and
maintain
Fire tube boiler can be used in small scale industries.
Fire tube boiler is relatively cheaper than water tube
boiler.
A fire tube boiler costs 25 to 40 percent less than a
comparatively sized water tube boiler.

18. DIS ADVANTAGES
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The fire tube boiler can not produce steam at a
pressure higher than 250 pounds per square inch.
Capacity of generated steam is limited. Fire tube
boilers are limited to approximately 2,500 HP, or
about 86,000 lb/hr.
Steam quality less as compared to WTB

19. WATER TUBE BOILER
In the water tube boilers, the
water is inside the tubes and
hot gases surround them.
 Used for high steam demand
and pressure requirements
 Capacity range of 4,500 –
120,000 kg/hour
 Combustion efficiency
enhanced by induced draft
provisions
 Lower tolerance for water
quality and needs water
treatment plant
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20. ADVANTAGES
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 To operate boiler at a high capacity, the water tube
packaged boiler is best.
 Water tube boiler packages are designed to handle larger
capacities, up to approximately 650,000 lb/hr, which is
equivalent to about 19,000 HP.
 A water tube boiler also is superior for high temperature
and steam pressure.
 It can operate at pressures up to 1,500 psi.
 For large-capacity loads, large design pressure
requirements, tracking rapid load swings or extreme
horsepower needs, the water tube boiler essentially is the
only choice.

21. EXTERNALLY FIRED AND INTERNALLY FIRED
 The boiler is known as externally fired if the fire
is outside the shell.
 In case of internally fired boilers, the furnace is
located inside the shell.
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22. FORCED CIRCULATION AND NATURAL CIRCULATION
In forced circulation type of boilers, the circulation
of water is done by forced pump.
In natural circulation type of boilers, circulation of
water in the boiler takes place due to natural
convention currents produced by the application of
heat.
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23. HIGHER PRESSURE AND LOW PRESSURE
BOILERS
 The boiler which produce steam at pressures of 80
bar and above are called high pressure boilers.
 The boilers which produce steam at pressure below
80 bar are called low pressure boilers.
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24. STATIONARY AND PORTABLE
Primarily, the boilers are classified as either
stationary or mobile.
Stationary boilers are used for power plant steam,
for central station utility power plants, for plant
process steam etc.
Mobile boilers or portable boilers include
locomotive type, and other small units for
temporary use at sites.
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25. SINGLE TUBE AND MULTI TUBE BOILER
THE fire tube boilers are classified as single tube and
multi-tube boilers, depending upon whether the fire
tube is one or more than one.
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MIANTENANCE

27. 1. Boiler Performance
2. Boiler blow down
3. Boiler feed water treatment
ASSESSMENT OF BOILER
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28. BOILER PERFORMANCE
• Causes Of Poor Boiler Performance
- Poor combustion
- Heat transfer surface fouling
- Poor operation and maintenance
- Deteriorating fuel and water quality
• Heat Balance : Identify heat losses
• Boiler Efficiency: Determine deviation from best
efficiency
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29. BOILER BLOW DOWN
• Controls ‘total dissolved solids’ (TDS) in the water
that is boiled
• Blows off water and replaces it with feed water
• Conductivity measured as indication of TDS levels
• Calculation of quantity blow down required:
Feed water TDS x % Make up water
Maximum Permissible TDS in Boiler water
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30. BENEFITS
• Lower pretreatment costs
• Less make-up water consumption
• Reduced maintenance downtime
• Increased boiler life
• Lower consumption of treatment chemicals
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31. Boiler Feed Water Treatment
 Quality of steam depend on water treatment to
control
 Steam purity
 Deposits
 Corrosion
 Efficient heat transfer only if boiler water is free
from deposit-forming solids
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